Recovering oil from a subterranean carbonaceous formation

Claim 2

In a process for recovering hydrocarbons from a permeable subterranean carbonaceous formation which comprises injecting a disaggregating fluid into contact with a subterranean carbonaceous formation under conditions sufficient to form at least a minor amount of finely-divided, unconsolidated, fluid-surrounded, solid particles, and at least some bitumen; injecting fluid A into contact with at least some of said particles; withdrawing fluids containing at least a minor portion of said bitumen from said cavity at a level higher than that where fluid A is injected; adjusting the rate of fluids injected and withdrawn so that a circulation current is established within said formation sufficient to suspend at least a minor portion of said solid particles in said fluid; and recovering hydrocarbon material from the fluids withdrawn; the improvement which comprises radially extending the region of the current upflow throughout a wider region of the subterranean formation.

Claim 3

The process of claim 1 wherein the region of current up-flow is radially extended throughout a wider region of the subterranean formation by increasing the permeability of the formation in the region radially extending horizontally from the point of injection of fluid A.

Claim 4

The process of claim 2 wherein the carbonaceous formation is oil shale and fluid A is steam which is injected at a level under at least a portion of said particles.

Claim 5

The process of claim 3 which comprises increasing the permeability of the lower portion of the formation which radially extends horizontally from the point of injection of fluid A by positioning large inert objects in the region radially extending horizontally from the point of injection of fluid A.

Claim 6

A process for recovering hydrocarbons from a carbonaceous formation which comprises forming a void region extending radially under a substantial portion of said formation; filling said void region with inert objects to form a radiallY extending region substantially permeable to fluid; injecting a disaggregating fluid into contact with said subterranean carbonaceous formation above said inert object-filled cavity, under conditions sufficient to form at least a minor amount of finely-divided, unconsolidated, solid particles, at least some free bitumen and a fluid-filled cavity; injecting fluid A into contact with at least some of said particles; withdrawing fluids containing at least a minor portion of said bitumen from said fluid-filled cavity from a level higher than that where fluid A is injected; adjusting the rate of fluid injected and withdrawn so that a circulation current is established within said formation sufficient to suspend at least a minor portion of said particles in said fluid; and recovering hydrocarbon material from the fluid withdrawn.

Claim 7

A process for recovering hydrocarbons from a carbonaceous formation which comprises forming a void region extending radially under a substantial portion of said formation; filling said void region with inert objects to form a radiallY extending region substantially permeable to fluid; injecting a disaggregating fluid into contact with said subterranean carbonaceous formation above said inert object-filled cavity, under conditions sufficient to form at least a minor amount of finely-divided, unconsolidated, solid particles, at least some free bitumen and a fluid-filled cavity; injecting fluid A into contact with at least some of said particles; withdrawing fluids containing at least a minor portion of said bitumen from said fluid-filled cavity from a level higher than that where fluid A is injected; adjusting the rate of fluid injected and withdrawn so that a circulation current is established within said formation sufficient to suspend at least a minor portion of said particles in said fluid; and recovering hydrocarbon material from the fluid withdrawn.

Claim 8

The process of claim 5 wherein the carbonaceous formation is nahcolite-containing oil shale, and said void region is formed by leaching out a region which is substantially entirely nahcolite.

Claim 9

A PROCESS FOR RECOVERING OIL FROM OIL SHALE WHICH COMPRISES LOCATING AN UNDERGROUND REGION IN A NAHCOLITE-CONTAINING OIL SHALE FORMATION WHEREIN SAID REGION IS OF ONLY MODERATE NAHCOLITE RICHNESS, LEACHING SAID REGION WITH A NAHCOLITE SOLVENT TO FORM A FIRST PERMEABLE ZONE OF RELATIVELY LARGE BLOCKS OF OIL SHALE RUBBLE WHICH ZONE IS LOCATED UNDER AN OIL SHALE FORMATION, FORMING A RUBBLED ZONE ABOVE SAID FIRST PERMEABLE ZONE, INJECTING A DISAGGREGATING FLUID INTO CONTACT WITH SAID RUBBLED ZONE UNDER CONDITIONS SUFFICIENT TO FORM AT LEAST A MINOR AMOUNT OF FINELY-DIVIDED, UNCONSOLIDATED, FLUIDSURROUNDED, SOLID PARTICLES, AND AT LEAST SOME BITUMEN, INJECTING FLUID A INTO SAID FIRST PERMEABLE ZONE PARTICLES, WITHDRAWING FLUIDS CONTAINING AT LEAST A MINOR PORTION OF SAID BITUMEN FROM SAID RUBBLED ZONE AT A LEVEL HIGHER THAN THAT WHERE FLUID A IS INJECTED, ADJUSTING THE RATE OF FLUIDS INJECTED AND WITHDRAWN SO THAT A CIRCULATION CURRENT IS ESTABLISHED WITHIN SAID FORMATION SUFFICIENT TO SUSPEND AT LEAST A MINOR PORTION OF SAID SOLID PARTICLES IN SAID FLUID, AND RECOVERING HYDROCARBON MATERIAL FROM THE FLUIDS WITHDRAWN.

Claim 10

A PROCESS FOR RECOVERING OIL FROM OIL SHALE WHICH COMPRISES LOCATING AN UNDERGROUND REGION IN A NAHCOLITE-CONTAINING OIL SHALE FORMATION WHEREIN SAID REGION IS OF ONLY MODERATE NAHCOLITE RICHNESS, LEACHING SAID REGION WITH A NAHCOLITE SOLVENT TO FORM A FIRST PERMEABLE ZONE OF RELATIVELY LARGE BLOCKS OF OIL SHALE RUBBLE WHICH ZONE IS LOCATED UNDER AN OIL SHALE FORMATION, FORMING A RUBBLED ZONE ABOVE SAID FIRST PERMEABLE ZONE, INJECTING A DISAGGREGATING FLUID INTO CONTACT WITH SAID RUBBLED ZONE UNDER CONDITIONS SUFFICIENT TO FORM AT LEAST A MINOR AMOUNT OF FINELY-DIVIDED, UNCONSOLIDATED, FLUIDSURROUNDED, SOLID PARTICLES, AND AT LEAST SOME BITUMEN, INJECTING FLUID A INTO SAID FIRST PERMEABLE ZONE PARTICLES, WITHDRAWING FLUIDS CONTAINING AT LEAST A MINOR PORTION OF SAID BITUMEN FROM SAID RUBBLED ZONE AT A LEVEL HIGHER THAN THAT WHERE FLUID A IS INJECTED, ADJUSTING THE RATE OF FLUIDS INJECTED AND WITHDRAWN SO THAT A CIRCULATION CURRENT IS ESTABLISHED WITHIN SAID FORMATION SUFFICIENT TO SUSPEND AT LEAST A MINOR PORTION OF SAID SOLID PARTICLES IN SAID FLUID, AND RECOVERING HYDROCARBON MATERIAL FROM THE FLUIDS WITHDRAWN.